Suicide Signs Loom in Pair of Surveys

Article excerpt

Two new studies provide behavioral clues to the likelihood of attempting or completing suicide among members of two disparate groups: predominantly white, middle-aged nurses and teenagers of both sexes and varied ethnic backgrounds.

Among nurses tracked for 12 years, suicides rose markedly as cigarette smoking increased. And in a large sample of students in public high school, a particularly strong association emerged between thinking about or attempting suicide and committing aggressive acts such as carrying weapons and fighting.

Both studies, and a comment on the findings by psychiatrist David Shaffer of the New York State Psychiatric Institute in New York City, appear in the February AMERICAN JOURNAL OF PUBLIC HEALTH.

No decisive explanation exists for the connection between cigarette smoking and suicide, concludes a scientific team headed by David Hemenway, an epidemiologist at the Harvard School of Public Health in Boston. The researchers consider it unlikely that smoking causes suicide in any direct way. However, they note that smokers suffer increased rates of alcoholism and cancer, both of which boost the risk of carrying out a suicide, according to previous studies.

Independent data indicate that common genetic factors may predispose some people to both cigarette smoking and severe depression; the latter poses a major risk of suicide (SN: 1/30/93, p.71).

Hemenway and his co-workers studied more than 100,000 female registered nurses, age 30 to 55, living in 11 states. Participants completed questionnaires mailed every two years from 1976 to 1988. The researchers obtained death certificates for volunteers who died during the study; these documents provide a conservative estimate of the number who killed themselves.

Compared with those who had never smoked, women who smoked one to 24 cigarettes daily displayed twice the likelihood of committing suicide, and those smoking 25 or more cigarettes daily exhibited four times the likelihood of committing suicide, Hemenway's team contends. …